Heretofore, as a laser radar device that combines a range finding mode where a range to a specified place on a target is measured with an imaging mode where a three-dimensional shape of the target is measured, the devices disclosed in Patent Document 1 and Non-Patent Document 1, for instance, are known.
In the conventional laser radar devices (imaging mode) disclosed in Patent Document 1 and Non-Patent Document 1, a laser that is a transmission pulse is formed linearly to be transmitted, and scattered light from the target with respect to the laser is received by linearly arrayed elements of an array receiver, whereby ranges to points on the target corresponding to views of the elements are instantly measured. That is, a cross-sectional shape of the target is instantly measured. When this measurement is repeated while scanning in a direction orthogonal to the linear array by a one-dimensional scanner, a two-dimensional range image is acquired. Then, based on the acquired range image and angles in transmission and reception directions corresponding to the images, a three-dimensional shape of the target is acquired.
In a condition where the imaging mode functions properly, it is obvious that the range finding mode is also operable. When the laser radar device is employed, an application to a safe landing sensor for detecting an obstacle in landing a planetary exploration spacecraft on a planet, and a docking sensor between objects, for example, satellites is promising.